This invention relates to an apparatus and process for infusing liquid dyestuff into synthetic yarn at the point of fiber production. The apparatus and process has application with any synthetic filament fiber, including but not limited to nylon, polyester and polypropylene. The process can be carried out on partially-oriented yarn (xe2x80x9cPOYxe2x80x9d) which is subsequently texturized by one of several known processes, on fully-oriented yarn, or on yarn which is left in its flat state.
Current technology for providing color to synthetic yarn is based on the principle of combining natural, white polymer feedstock together with dye to produce a colored material called xe2x80x9cmaster batch.xe2x80x9d Master batch is initially produced in chip form, and is then melted and extruded into filaments. This process is described in the Haggard, et al., U.S. Pat. No. 5,516,476, (xe2x80x9c""476 Patentxe2x80x9d), which is incorporated herein by reference. Melting and extruding master batch chips has several significant disadvantages, including higher cost due to higher waste, increased time and costs associated with master batch production, and various adverse effects on downstream processes. Since the chip material is produced in batches, it is often difficult to achieve precise color matches from batch to batch. A color dryer is required, further adding to costs. Static electricity during the run can cause the master batch chips to stick together and not feed properly. Chip size is also very important, and any significant variation can cause streaks and other defects in the filament fibers ultimately produced. Furthermore, variations in the quality of the process control employed as a master batch undergoes color drying and extrusion often adversely affect the final product. For example, heat variations within the extruder can cause color streaks or shifts in a master batch. Unfortunately, the ability to make adjustments to the color during processing is very limited, because such adjustments can only be made from light to dark or from dark to light on the shade. Complete color changes require complete clearing of the entire extrusion line, which results in wasted material and may create 8 to 12 hours of downtime, which significantly delays the extrusion process.
The apparatus and process according to the present invention eliminates altogether the need to produce master batches of colored polymer. Because master batches are not used, the need for a master batch production line is completely eliminated. A side-arm extruder, master batch feed system and master batch dryer are no longer required, and the costs, inconveniences and inefficient use of time associated with master batch production are completely eliminated. Color repeatability is improved at reduced production and capital investment costs. Moreover, change from one color to another is very rapid, permitting quicker response to market demands for particular colors.
The novel apparatus and process of the present invention achieves these improvements by injecting non-molten liquid dye directly into the spin pack after the screens and immediately before the point at which extrusion of the molten polymer occurs through the spinnerette. Introducing the liquid dye into the spin pack assembly upstream from the spinneret further permits color to be added to the polymer without passing the dye through an extruder. Bypassing the extruder saves additional time and eliminates costs typically associated with the cleaning and maintenance involved in changing colors during conventional master batch production processes.
The liquid dye used in the present invention is less expensive than master batch chips. The color may be quickly adjusted during production runs, which reduces overall waste. Furthermore, the exact color may be repeated from one batch to another and within the same batch. Color may also be changed on each thread line, or on multiple thread lines by position, which further enhances production flexibility. Since the liquid dye is not passed through an extruder prior to entering the spinneret, streaks in the final product are eliminated that would have otherwise been created due not only to chip size variation, but also to exposure of the dye to heat and oxidation within the extruder. Polymer strength is also improved, as are light fastness and weathering characteristics.
Using the apparatus and process of the present invention results in increased customer satisfaction. Eliminating the use of master batches reduces the time required for shade match approval by two to six weeks, reduces production lead times, permits small lot production quantities to be offered, and allows specific shades to be reproduced on re-orders. Such competitive advantages, along with the improvements in the coloring process described above, are unique to the present invention, and have thus far not been achieved using conventional master batch techniques.
Therefore, it is an object of the invention to provide an apparatus and process for dyeing polymer material during the filament extrusion process.
It is another object of the invention to provide an apparatus and process for dyeing polymer material during the filament extrusion process using a liquid dye.
It is another object of the invention to provide an apparatus and process for dyeing polymer material during the filament extrusion process using a liquid dye that does not have to be mixed with a molten carrier prior to being introduced to the molten polymer material from which the fiber filaments are formed.
It is another object of the invention to provide an apparatus and process for dyeing polymer material which does not require the use of a master batch, and eliminates all of the materials, equipment and costs associated with such use.
It is another object of the invention to provide an apparatus and process for dyeing polymer material which results in fiber filaments having one or more colors that can be accurately duplicated from one batch to another.
It is another object of the invention to provide an apparatus and process for dyeing polymer material which improves the strength, lightfastness, and weathering characteristics of the synthetic fiber filaments ultimately produced.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a method for infusing liquid dyestuff into synthetic yarns at the point of fiber production, which includes the step of providing a molten polymer, at least one non-molten liquid dye, and a spin pack assembly adapted for receiving and mixing the molten polymer and the non-molten liquid dye therein to form a colored molten polymer composition. The spin pack assembly includes a screen for filtering the molten polymer therethrough, and a spinneret adapted for receiving and extruding the colored molten polymer composition therethrough to form a plurality of colored fibers adapted for being formed into the synthetic yarns. The liquid dye and the molten polymer are metered into the spin pack assembly and mixed together between the screen and the spinneret to form the colored molten polymer composition. The polymer composition is then extruded through the spinneret, thereby forming the colored fibers.
According to one preferred embodiment of the invention, a method of infusing liquid dyestuff into synthetic yarns at the point of fiber production is disclosed in which a molten polymer, a plurality of non-molten liquid dyes, and a spin pack assembly are provided. The spin pack assembly is adapted for receiving and mixing the molten polymer and the non-molten liquid dyes therein to form a colored molten polymer composition, and includes a screen for filtering the colored molten polymer composition therethrough and a spinneret adapted for receiving and extruding the molten polymer composition therethrough to form a plurality of colored fibers adapted for being formed into the synthetic yarns. The liquid dyes and the molten polymer are metered into the spin pack assembly; and mixed together between the screen and the spinnneret to form the colored molten polymer composition, which is then extruded through the spinneret, thereby forming the colored fibers.
According to another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns at the point of fiber production is disclosed which includes the step of providing a molten polymer, at least one non-molten liquid dye, and a spin pack assembly. The spin pack assembly includes a plurality of plates in fluid communication with one another and adapted for receiving and mixing the molten polymer and the non-molten liquid dye therein to form a colored molten polymer composition. The spin pack assembly also includes a spinneret positioned downstream from and in fluid communication with the plates for receiving and extruding the colored molten polymer composition into a plurality of colored fibers adapted for being formed into the synthetic yarns. The liquid dye and the molten polymer are metered into the plates and mixed together therein to form the colored molten polymer composition. The colored molten polymer composition is then extruded through the spinneret to form the colored fibers.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns at the point of fiber production is disclosed, including the step of providing a molten polymer, at least one non-molten liquid dye, and a spin pack assembly including a first mix plate positioned upstream from a second mix plate and a spinneret positioned downstream from the second mix plate. The first and second mix plates are in fluid communication with one another and are adapted for receiving and mixing the molten polymer and the non-molten liquid dye there between to form a colored molten polymer composition. The spinneret is positioned downstream from and is in fluid communication with the second mix plate for receiving and extruding the colored molten polymer composition therethrough to form a plurality of colored fibers adapted for being formed into the synthetic yarns. The liquid dye and the molten polymer are metered into the first mix plate and mixed together between the first and second mix plates to form the colored molten polymer composition. The colored molten polymer composition is then extruded through the spinneret to form the colored fibers.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns at the point of fiber production is disclosed and includes the step of providing a molten polymer and at least one non-molten liquid dye. A spin pack assembly is also provided and includes a first mix plate positioned upstream from a second mix plate. The first and second mix plates define a plurality of intersecting passageways extending there between. Each of the passageways is adapted for receiving and mixing the molten polymer and the non-molten liquid dye therein to form a colored molten polymer composition. The spin pack assembly also includes a spinneret positioned downstream from and in fluid communication with the passageways for receiving and extruding the colored molten polymer composition to form a plurality of colored fibers adapted for being formed into the synthetic yarns. The liquid dye and the colored molten polymer are metered into a respective one of the passageways and then mixed together within the passageways to form the colored molten polymer composition. The colored molten polymer composition is then extruded through the spinneret to form the colored fibers.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns at the point of fiber production is disclosed including the step of providing a molten polymer, at least one non-molten liquid dye, and a spin pack assembly including a first mix plate positioned upstream from a second mix plate, the first and second mix plates including respective complementary lower and upper surfaces. The lower and upper surfaces define a plurality of complementary first and second passageways, respectively, positioned in juxtaposing relation to and fluidly communicating with one another for receiving and mixing the molten polymer and the non-molten liquid dye therein to form a colored molten polymer composition. The spin pack assembly also includes a spinneret positioned downstream from and in fluid communication with the second mix plate for receiving and extruding the molten polymer composition therethrough to form a plurality of colored fibers adapted for being formed into the synthetic yarns. The method further includes the steps of metering the liquid dye and the molten polymer into a respective one of the first passageways and mixing the liquid dye and the molten polymer together within the first and second passageways to form the colored molten polymer composition. The colored molten polymer composition is then extruded through the spinneret to form the colored fibers.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns is disclosed, wherein the step of providing at least one non-molten liquid dye includes providing a non-molten liquid dye which is soluble in the molten polymer.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns is disclosed, wherein the step of providing at least one non-molten liquid dye includes providing a non-molten liquid dye which is insoluble in water.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns is disclosed, wherein the step of providing at least one non-molten liquid dye includes providing a non-molten liquid dye having a boiling point greater than the melting point of the molten polymer.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns is disclosed, wherein the step of providing a molten polymer includes providing a molten polymer selected from a group consisting of polyester, polypropylene, nylon-6.
According to yet another preferred embodiment of the invention, a method for infusing liquid dyestuff into synthetic yarns is disclosed, wherein the step of providing a non-molten liquid dye includes providing a non-molten liquid dye having at least one pigment which includes at least one primary color proportioned to produce a preselected color.
According to yet another preferred embodiment of the invention, a liquid color feed system for infusing liquid dye into synthetic yarns at the point of fiber production is disclosed. The feed system includes at least one non-molten liquid dye and a molten polymer received and stored within a respective one of a plurality of holding vessels, and a plurality of pressurized feed pumps. Each of the pumps is fluidly connected to a respective one of the holding vessels for pumping preselected amounts of the liquid dye and the molten polymer from the holding vessels. The feed system also includes a spin pack assembly fluidly connected to the feed pumps and including a screen for filtering the molten polymer therethrough, first and second mix plates positioned downstream from the screen and adapted for receiving and mixing the molten polymer and the non-molten liquid dye therebetweento form a colored molten polymer composition, and a spinneret adapted for receiving and extruding the colored molten polymer composition therethrough to form a plurality of colored fibers adapted for being formed into the synthetic yarns.
According to yet another preferred embodiment of the invention, the liquid color feed system further includes a centralized dye dispensing system removably connected to each of the vessels for selectively dispensing predetermined amounts of a plurality of non-molten liquid dyes into the vessels.
According to yet another preferred embodiment of the invention, the non-molten liquid dye is soluble in the molten polymer
According to yet another preferred embodiment of the invention, the non-molten liquid dye is insoluble in water.
According to yet another preferred embodiment of the invention, the non-molten liquid dye has a boiling point greater than the melting point of the molten polymer.
According to yet another preferred embodiment of the invention, the molten polymer is selected from a group consisting of polyester, polyethylene terephthalate, nylon-6, and nylon-66.
According to yet another preferred embodiment of the invention, the liquid dye includes at least one pigment having at least one primary color proportioned to produce a preselected color.